Microsoft Excel Add-in Development Services
Our Excel Add-in Development Expertise
Developing Excel add-ins starts with where your users work. We build cross-platform Office.js add-ins and Windows-specific VSTO solutions with C#/.NET, selecting the right stack for platform, performance, and deployment needs. We also modernize legacy Excel extensions while preserving essential business logic and workflows.
Explore Our Expertise
- 25+ years of Microsoft development experience
- Office.js, VSTO, C# and .NET development
- Custom functions, task panes and workflow automation
- Excel for Windows, Mac, web and iPad
- Microsoft Marketplace publishing and centralized deployment
Office.js, VSTO or XLL: Which Excel Add-in Fits Your Task
SCAND selects the Excel add-in technology around your business goals, target platforms, performance requirements, and deployment model. We design both cross-platform solutions and Windows-specific extensions, using the stack that best fits the product.
For teams targeting Windows, Mac, web, and iPad, we typically use Office.js. It supports custom functions, task panes, API integrations, and cloud-connected workflows. For deeper Windows desktop automation, we work with VSTO and .NET. When performance is the priority, we use XLL for calculation-heavy scenarios.
Office.js add-in
VSTO add-in
XLL add-in
VBA add-in (.xlam)
Platforms
Windows, Mac, web, iPad
Windows only
Windows only
Windows, Mac with limitations
Language
JavaScript, TypeScript
C#, VB.NET
C/C++, C# with Excel-DNA
VBA
Best for
Cross-platform tools, custom functions, cloud data
Deep desktop automation
High-performance calculations
Quick internal macros
Distribution
Microsoft Marketplace, admin center
MSI, ClickOnce
File or installer
File
Excel Add-in Development Services We Offer
Our custom Excel add-in development services draw on SCAND’s practice as a Microsoft Office add-in development company: we build solutions for automation, reporting, integrations, and complex business workflows.
Custom Functions for Excel
We build custom Excel functions with Office.js for advanced calculations, API-driven data, and real-time updates. Functions can share a runtime with the task pane, allowing both components to use the same state, services, and business logic within one add-in.
Financial Reporting Automation
Add-ins for financial reporting automate everyday tasks, from consolidations and computations to changing formats. SCAND solutions help you avoid errors with respect to the principles of accounting and allow for deadlines to be met. They enable leaders to spend less time on routine processes and more time on strategic planning.
Data Visualization and Formatting in Excel
We design add-ins that turn raw data into clear, interactive dashboards and reports. Advanced charting, formatting tools, and visualization options help teams better understand business trends and make informed decisions. Our solutions transform Excel into an intuitive platform for business data visualization.
Workflow Automation
We develop Excel add-ins that automate data imports, formatting, validation, reporting, and project workflows. Teams can assign tasks, allocate resources, track deadlines, and manage project data directly in Excel, reducing manual work, improving consistency, and giving managers clearer visibility into project progress.
CRM, ERP and API Integrations
Through Microsoft Office integration, we build Excel add-ins that connect with CRM, ERP, third-party APIs, and Microsoft services. Using the Microsoft Graph Excel API, we enable reliable data exchange, reduce manual transfers, and make Excel part of a connected business workflow.
Our AI-powered assistants, including solutions built with Microsoft 365 Copilot, bring intelligent features directly into Excel. They can provide predictive analytics, smart recommendations, and automated insights to support better decision-making. These assistants help teams unlock the full potential of their data without leaving the familiar Excel environment.
XLL Add-ins in C/C++ for Financial Applications
We develop high-performance UDFs and calculation libraries in C/C++ using the Excel C API, including multithreaded processing and C# wrappers with Excel-DNA. Our expertise in financial applications using Excel add-in development in C/C++ covers pricing, risk models, and real-time market data.
Cross-Platform Enterprise Add-ins
We build cross-platform Excel add-ins with Office.js for Windows, Mac, Office on the web, and iPad, and Windows-specific solutions with VSTO or XLL where needed. Our Office.js add-ins can support Microsoft Entra ID single sign-on and centralized deployment for enterprise environments.
VSTO, XLL and VBA Migration to Office.js
We modernize legacy Excel solutions by moving suitable VSTO, XLL, and VBA functionality to Office.js. Our VSTO expertise preserves business logic, while legacy modernization reduces technical debt and expands platform support. Windows-only features remain separate when Office.js cannot replace them.
Hire Excel Add-in Developers
We provide specialists who create custom add-ins for Excel to speed up report preparation, improve analytics, and optimize project management. Our teams work on both individual tasks and in a permanent partnership format, providing your business with flexibility and efficiency.
Technologies and Tools
To deliver high-quality, scalable, and efficient Excel add-ins, SCAND relies on a proven technology stack that ensures performance, integration, and cross-platform compatibility:
Microsoft Office for Windows Desktop
- .NET
- VSTO
- Excel-DNA
JavaScript Frameworks
- Office.js
- Excel JavaScript API
- React or Angular
- Fluent UI
Programming Languages
- C#
- C/C++
- JavaScript
- TypeScript
- VBA
Excel-Specific Tools
- Custom functions
- Excel C API
- XLL SDK
- Office Scripts
Integration APIs
- Microsoft Graph API
- Microsoft Entra ID
Cloud Platforms
- Azure
- AWS
- Google Cloud
Platforms
- Windows
- macOS
- Web version of Excel
Trusted Software Development Company
For over 25 years, SCAND has been delivering secure, high-load software solutions for startups, SMBs, and global enterprises (including NASA, IBM, Cisco, FedEx, Bank of America, Siemens, and others). Our dedicated development teams support clients at every stage of the software development process — from idea and consulting to maintenance and support.
Our Approach to Excel Add-in Development
At SCAND, we follow a structured and transparent process to deliver Excel add-ins that are reliable, scalable, and perfectly aligned with business needs. From idea validation to long-term support, we guide you through every stage of development:
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2. UI/UX Design
Our team designs intuitive interfaces that seamlessly integrate into Excel’s environment. This means your employees won’t have to spend a long time getting used to the add-in and will be able to use it without any extra effort.
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3. Technology Selection & Development
Depending on your needs, we choose the right technology stack (.NET & VSTO, Office.js, APIs) to ensure flexibility and scalability. Our engineers then develop the core functionality with a focus on stability, speed, and security.
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4. Testing & Cross-Platform Compatibility
We conduct functional, performance, and compatibility testing to make sure the add-in works reliably across different Excel versions, as well as on Windows and macOS (.NET & VSTO for Windows, or Office.js for cross-platform).
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5. Microsoft Marketplace (formerly AppSource) Deployment
We prepare add-ins for Microsoft Marketplace submission, including Partner Center validation, which typically takes four to six weeks and often needs more than one submission. For internal solutions, we support centralized deployment through the Microsoft 365 admin center and provide post-release maintenance and updates.
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1. Business & Requirements Analysis
We start by gathering your requirements, identifying key challenges, and defining the goals of the Excel add-in (automation, reporting, visualization, or integration). Based on this, we outline a clear roadmap for development.
Industry Solutions for Excel Add-ins
SCAND delivers Excel add-ins tailored for specific industries, helping companies simplify routine tasks, improve accuracy, and get more value out of their data.
Our Excel add-ins streamline financial reporting, automate consolidation, and ensure compliance with accounting standards. They help finance teams reduce manual effort, minimize errors, and deliver accurate reports on time.
We build add-ins that simplify contract analysis, case management, and compliance tracking. Legal professionals can organize data, automate document handling, and gain quicker insights directly in Excel.
SCAND develops Excel-based tools for managing patient records, scheduling, and reporting. This helps doctors and administrators keep their data organized, work more efficiently, and support compliance requirements.
We create Excel add-ins for teachers, trainers, and administrators, enabling automated grading, lesson planning, and performance tracking. These tools enhance learning outcomes and reduce administrative workload.
Our Excel add-ins help online businesses keep track of inventory, monitor sales, and conveniently view results in dashboards. Working with data becomes easier, and decisions are made faster and with greater confidence, which directly impacts the company’s growth.
We build Excel add-ins for shipment planning, route calculations, rate management, and logistics reporting. Teams can process operational data directly in Excel, compare delivery options, and reduce manual work across transportation workflows.
Built by Experts. Accelerated by AI.
We can enhance your solutions with AI tools where they bring real value or leave development completely traditional.
Engagement Models
SCAND offers flexible collaboration models so you can choose the one that best fits your Excel add-in development needs.
A flexible model where you pay only for the actual hours and resources used. Perfect for Excel add-in projects with changing requirements or an undefined scope.
Extend your in-house team with skilled Excel add-in developers. This model allows you to quickly scale expertise without the overhead of hiring full-time staff.
Get a dedicated team fully focused on your Excel add-in projects. You have complete control over tasks, priorities, and workflows, while we ensure seamless delivery and long-term support.
Benefits of Choosing SCAND for Excel Add-in Development
Partnering with SCAND for Excel plugin development ensures you get powerful, reliable, and business-oriented solutions designed to maximize efficiency and growth.
Tailored to Your Workflows
Your processes define the solution. We adapt functionality, data flows, and interfaces to the way teams already work in Excel.
Native Excel Experience
Smooth adoption starts with a familiar interface. We use Fluent UI, ribbons, and task panes to bring new capabilities directly into Excel, so you can use your add-in without learning a new interface or changing how you work.
Office.js, VSTO and C/C++ XLL in One Team
Different requirements call for different technologies. SCAND covers Office.js, VSTO, .NET, and XLL, supported by 25+ years of C/C++ development experience.
Transparent Estimates and Support
We provide a clear estimate, ongoing post-release support, and cost-efficient expertise tailored to your needs without compromising functionality.
Scalable Architecture
Our add-ins are built with scalability in mind, allowing your solution to evolve as your business grows and new requirements arise.
AI-Assisted Automation
We add AI features to Excel add-ins, such as smart recommendations and automated insights, and use AI tools in our own delivery workflow to speed up development.
Related Cases
- .NET
- AWS/Azure
- C++
- LangChain
- LLMs
- Python
Latest Reviews from Our Clients
Sr. Account Director Mid-Market
Coupa Deutschland GmbH
It was a great experience working with SCAND on e-Procurement projects during my time at OpusCapita. The team was professional and competent. Keep up the great work!
Managing Director
prodexa GmbH
The SCAND team has been an incredibly reliable and skilled development partner for jCatalog for many years, consistently delivering high-quality services with a proactive approach.
Product Manager
jCatalog Software AG (or OpusCapita GmbH)
Over the years of working together, the SCAND team has always been a reliable pillar of support for me. Along the way, we’ve built not only a strong professional relationship but also meaningful personal connections. It has truly been a pleasure collaborating with you.
Outsourcing Manager at Owlcat Games
Working with SCAND on customizing SourceGit was a genuinely positive experience. Their team was responsive, collaborative, and easy to work with throughout the project. We value their cooperative approach and would confidently recommend them as a reliable development partner.
Managing Product Owner at GIPmbh
We have been working with SCAND on the development of a custom Outlook Add-In that converts documents directly from Outlook and transfers them seamlessly into our software platform. We highly recommend them to anyone looking for a skilled and dependable software development team...
Chief Technology Officer
Wiztech Group
Great work on our products — web applications in the gaming domain. The SCAND software developers worked highly professionally and made valuable contributions to the successful implementation of every project they were involved in.
Sales & Marketing Manager, Smartstaff AS
Throughout our long-standing collaboration, the team has consistently delivered high-quality service. Over time, we’ve developed a strong and genuinely friendly working relationship, which has positively influenced the outcomes of our joint efforts.
Founder at Spin Pass
SCAND went above and beyond, and I was very satisfied with the result. Their team was communicative, patient, and took the time to fully understand the project. Above all, they were professional and easy to work with, and I would definitely recommend SCAND for their expertise and software development skills.
Founder of TreeNinjaAI
What might have taken 18 months was completed in about 6, with SCAND contributing for 3.5 months. Despite my non-engineering background, their support and modern AI capabilities enabled us to build unique features and integrations in a single application.
FAQs
